Electric switch



June 7, 1927.

G. A. BQRNHAM ELECTRIC SWITCH Filed July 5, 1922 E: I I

"' Irwenfor.

Patented June 7, 1927.

. UNITED STATES PATENT()"F FI1C.E .V,

enonon A. BURNHAM, or serious, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGN-.

MENTS, TO CONDIT ELECTRICAL MA NUFACTUBING-CORPORATION, OF BOSTON, A

MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

ELECTRIC swrrcn.

Application filed July 3, 1922. Serial no. 572527.

This invention relates to an electric switch particularly adapted, although not limited; to the. control 01'' small inductionmotors.

Bin induction motor, when starting, requires momentarily a considerably greater current than when running at full load, and the current carried by the contact members an eli ective manner to reduce arcing at the contact members due to the heavy starting Laurent, and specifically, to provide a switch iirranged to complete the circuit rapidly; and

the switch may open the circuit at a more moderate speed.

i'urther objectis to provide simple and eli'cctive manually-controlled switch operating mechanism including a spring arranged to close the switch rapidly and hold it yieldingly in bothopen and closed positions.

A further object is generally to improve the construction and operation of electric switches.

This invention is described but not claimed in a co-pending application of George V. OIiIceTl'e, Serial No. 572,536, filed July 3, 1922, and assigned to Sears B. Condit.

Fig. 1 is a sectional elevation of the switch en'ibodying the invention.

Fig. 2 is a section along line 1-1.of Fig. 2.

As here shown, the switch embodying the invention may include the casing having the upper casing portion 10 and the lower casing portion 11. which is adapted to contain oil in which the switch members are immersed. A supporting plate 12, which may be made of suitable insulating material, as porcelain, is or may be received within the upper casing portion 10 and is adapted to support the switch components.

The stationary switch members may comprise the relatively flexible strip-members 14 and 15 which are secured to and depend from the lower face of the supporting plate,

and said members'maybe reflexed outwardly and terminate in the detachable contact members 16 and'17. i I

The movable switch member may include the ar1n18 which may be pivota'l'ly-sup ported in a bracket 19, and said bracketmay 1 be secured to and dependfrom the lower face of said supporting plate. fin insulating bar 20 may be secured to the free end of said arm 18 and. a contact or bridging mem- 'ber'21"m ay be secured to said bar 20; Said contact member 21 is adapted to be moved upwardly to engage saidstationary contact members 16 and 17 The switch operating mechanism embodying my invention may include a, preferably tension, spring 25 which may be connected to an ear 26 of the arm 18 and an ear 26 of a plate 27 secured to the lower face of the circulating plate, and, in accordance with my invention," said spring is arranged to bias the switch toward closed position and. constantly urge the arm 18 upward to'move the Contact member 21 to engage the stationary contact members 16 and 17. Means are providedto 'per 'nitisaid spring to act, whereby to close the switch, or to restrain it from acting,whereby tofhold the switch open. Said means' m'ay include the toggle. member including" the links 30which are A pivotally connected with the crank arm Said links 30 are pivotally Connected with the switch arm 18 and said crank arm 31 is fixed to an operating shaft 32, and said shaft may be rotatably supported in ears 33 struck up from said plate.

Said toggle is so arranged that, in the straightened position itis slightly overshot, as indicated ,in Fig. 1, and holds the switch open against/the urge of said spring 21'but, when the operating shaft 32 is rotated in a clock-wise directionto move the toggle over the dead center, said spring 25 acts to close the switch rapidly. The closed position of ghe switch is indicated in the dotted lines,

Means are provided to restrict the movement of the switch in openand closed positions and said means may comprise the ears 35 and 36 which may be struck up from said plate 27and disposed on opposite sides of the crank arm 31. Said crank arm 31 may engage the ear 36 to fix the switch-open position of the movable switch member, and said crank may engage the ear to fix the switch closed position of the movable switch member.

Said spring and toggle are so arranged that the toggle is held yieldingly by the spring in positions corresponding both to closed and open positions of the switch.

The operating shaft may be rotated by suitable externally disposed means as the key which may extend through an aperture in the upper casing portion 10 and be received on the end of the shaft and loosely connected therewith as by the screw 41-1 in the end of the shaft which is received loosely in the angularly elongated slot 42 in the key 10. The arrangement is such that a rotary movement of said key serves to rotate the shaftto move the toggle over the dead center and the spring therefore snaps the switch into closed position independently of further control from the key. The key, however, inust rotate the shaft through its full extent of rotary movement in the opposite direction to open the switch.

It is obvious that thestructure may be modified without departing from the spirit of the invention.

I claim:

1. In an electric switch including an enclosing casing, movable and stationary switch members and operating m chanism received therein, said movable switch mem-' ber comprising a pivoted arm, said operat ing mechanism including means to urge the switch members together, a rotatablyv supported operating shaftextended externally beyond the casing, links comprising'a toggle connecting said operating shaft and pivoted arm arranged to govern the action of said urging means, and an operating member connected loosely with said shaft externally of said casing.

2. In an electric switch, movable and stationary switch members, said movable switch member comprising a pivoted arm, and switch operating mechanism including a rotatably supported operating shaft, and links comprising a toggle connecting said operating shaft and pivoted arm, a spring associated with said pivoted arm arranged to urge said arm constantly toward switch closed position, said toggle arranged to govern the action of said spring, and an oper-. ating member having a loose connection with said shaft, whereby to permit said switch to he closed by said spring independently of a correJponding movement of said operating member 3. In an electric switch including an enclosing casing, movable and stationary switch members and operating mechanism received therein, said movable switch member comprising a pivoted arm, said operating mechanism including a rotatably supported operating'shaft extended externally beyond the casing and links coin n'ising a toggle connecting said operating shaft and pivoted arm, a spring associated with said pivoted arm arranged to urge said arm constantly toward switch closed position, said toggle arranged to govern the action of said spring and an operating member disposed externally of said casing having a loose connection with said operating shaft whereby to permit said spring to close the switch independently of tl'COJ'LQEiPOIICllHg movement ofsaid operating member.

In testimony whereof, I have signed my name to this specification.

.ononen A. BURNHAM. 

